PL205775B1 - Belted absorbent article and a method of producing a laminate for use as belt material - Google Patents

Abstract

Absorbent article such as a diaper and an incontinence guard provided with a pair of belt members (10a, b) intented to be fastened together around the waist of the wearer by fastening means (11, 12) and where said front portion (5), is provided with fastening means (8, 9) intended to be fastened to the belt members (10a, b), in such a way that the article will assume a pantlike shape, where the belt members (10a, b) form a part of the waist portions of the pant. The belt members (10a, b) comprise a flexible laminate of at least three layers, a first outer layer (14), a middle layer (16) and a second outer layer (15) of fibrous material bonded together in a bonding pattern (13) provided by ultrasonic, laser and/or heat, said bonding pattern (13) having a bonding area of no more than 10 %. The first outer layer (14) and said middle layer (16) have a creped structure of a plurality of raised areas (14a; 16a) separated by a plurality of non-raised areas formed by the bonding sites (13) of said bonding pattern, wherein the creped structure of the first outer layer (14) is more distinct with a greater height of said raised areas (14a) as compared to the middle layer (16).

Description

The present invention relates to an absorbent article and a method of making a flexible laminate for use as web elements on an absorbent article. The invention relates to an absorbent article, such as a diaper for children and adults, comprising a liquid-permeable topsheet, a liquid-impermeable backsheet and an absorbent body sandwiched therebetween, said article having a front portion, a rear portion and a crotch portion therebetween. and further provided with a pair of belt members attached to the rear portion, alternatively to the front portion of the article, which are intended to be fastened together around the waist of a wearer, and wherein said front portion, alternatively, said rear portion is provided with fastening means for for attachment to the belt elements such that the article takes the shape of a panty, with the belt elements forming part of the waist portions of the panty. The invention further relates to a method of manufacturing a flexible laminate for use as belt elements on an absorbent article, such as a baby diaper and an adult diaper.

Diapers for children and adults typically have a garment part holding the absorbent body in place against the wearer's body and fastening means that keep the garment part in place also during the user's movements. A common type of fastening means are adhesive tapes or touch-and-close hook and loop fasteners which attach directly the front and back of the absorbent article to each other. Moreover, it is known, for example from EP-A-0 287 388, EP-A-0 409 307, EP-A-0 605 012 and FR-A-2 586 558, to fix the front part to the rear part of the product by means of straps. The belt elements are typically attached to the back portion of the diaper and are intended to be secured together around the waist of the wearer, and the fastening elements provided in the front of the diaper are then intended to be attached to the outside of the belt elements. The straps allow a better diaper fit. The belt further simplifies the diaper change for children or adults, especially when the user is in a standing position.

One problem with such belts is that they can irritate the skin of the wearer since they come into direct contact with it and must be secured relatively firmly in order to achieve a proper fit and leakproofness of a baby or adult diaper. As a result of the close contact and friction between the belt and the skin, the skin is rubbed mechanically, causing irritation and even skin wounds. It is therefore important that the material used to form the inner surface of the belt is soft and skin-friendly. Belt materials addressing this problem are disclosed in WO 00/27330 and WO 01/00129.

As already mentioned, the outer surface of the belt should serve as a seating surface for the fastening elements on one of the belt elements and on the front part of the baby or adult diaper. In the case of hook and loop type fasteners, the outer surface of the belt should serve as the loop material cooperating with the hook material constituting said fastening means. For cost reasons, it is preferable to use a non-woven material for the loop material, but the substantially flat and smooth non-woven material does not always provide the necessary shear and peel strength to withstand the forces acting upon it during normal use of the article. A shear force is applied in a plane substantially parallel to the joining surfaces of the hook and loop members, and the peel force is applied in a direction substantially perpendicular to the joining surfaces of the hook and loop members.

WO 97/19665 discloses a loop fastening material in the form of a crinkled nonwoven layer attached to a support layer by means of a heat- or ultrasonic bonding pattern. The wrinkling of the material has been found to improve the loop function of the material. The use of this material as a suitable belt material is not disclosed.

It is an object of the present invention to provide a belt for absorbent articles that is comfortable to wear, tear-resistant and performs better as a loop material.

An absorbent article such as a baby diaper and an adult diaper having a liquid-permeable topsheet, a liquid-impermeable backsheet and an absorbent body sandwiched therebetween, the article having a front portion, a rear portion and a crotch portion therebetween, and moreover, it is provided with a pair of strap elements attached to the rear portion, alternatively to the front portion of the article, intended to be fastened together around the waist of the wearer by means of fastening means, and where on the front portion, alternatively of the rear portion, fastening means are provided to be fastened to the wearer. of the waist members in such a way that the article takes a pant-like shape, where the belt members form part of the waist portion of the panty, according to the invention, characterized in that the belt elements comprise a flexible laminate composed of at least three layers of a first outer layer. , middle layer and second layer external, made of fibrous material bonded to each other according to a bonding pattern made by ultrasonic, laser and / or thermal techniques, the bonding pattern having a bonding area of not more than 10%, and the first outer layer and the middle layer of the laminate have a crinkle structure composed of multiple areas raised areas separated by a plurality of non-raised areas formed by the seams of the seam pattern, where the crinkle structure of the first outer layer is, compared to the middle layer, clearer with the greater heights of the raised areas.

Preferably, the second outer layer of the laminate is substantially smooth and non-wrinkled. Preferably, the second outer layer of the laminate is used as the inner side of the belt elements to face the user, and the first outer layer of the laminate is used as the outer side of the belt elements to act as a seating surface for the fastening elements.

Preferably, the first outer layer is used as the loop material for the complementary hook material of the hook and loop fasteners.

Preferably, the bonding pattern has a bonding area of not more than 8%, preferably not more than 5%.

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Preferably, the bonding pattern has a bonding site density of from 1 to 15 bond sites per cm ² .

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Preferably, the bonding pattern has a bonding density of from 1 to 10 bonding sites per cm ² . Preferably, the middle layer is made of a relatively high tear strength fibrous material containing continuous fibers, such as spunbond and / or meltblown material. A method of producing a flexible laminate for use as belt elements on an absorbent article, such as a baby diaper and an adult diaper of the type mentioned above, according to the invention is characterized in that at least three layers are bonded together in a bonding station, the first outer layer, middle layer and second outer layer made of fibrous material according to a bonding pattern made by ultrasonic, laser and / or thermal techniques, the bonding pattern having a bonding area of not more than 10%, and the laminate layers having different web tensions and / or web speeds at the entrance to the bonding station such that the first outer layer has the lowest web tension and / or the lowest web speed, the second outer layer has the highest web tension and / or the highest web speed, and the middle layer has web tension and / or web speed that are greater than the first outer layer and less than the second j outer layer.

Preferably, the second outer layer has a web tension and / or web speed during bonding 15 to 50% greater than that of the first outer layer.

Preferably, the second outer layer has a web tension and / or web speed during bonding 18 to 33% greater than that of the first outer layer.

Preferably, the middle layer has a web tension and / or web speed during bonding 5 to 40% greater than that of the first outer layer.

Preferably, the middle layer has a web tension and / or web speed during bonding 9 to 18% greater than that of the first outer layer.

The subject of the invention in an exemplary embodiment is shown in the drawing, in which fig. 1 shows a diaper with belts according to the invention, in a perspective view, schematically, fig. 2 - a laminate according to the invention, schematically, and fig. 3 - a device for carrying out the method according to the invention. the invention is shown schematically in a side view.

Figure 1 shows an embodiment of a diaper 1 for children or adults comprising a liquid-permeable topsheet 2, a liquid-impermeable backsheet 3 and an absorbent body 4 interposed therebetween 4. The liquid-permeable topsheet 2 may be of any suitable material. for this purpose, for example non-woven material such as filament spunbond material, meltblown material, a thermally bonded fiber web such as a carded fiber web. The outer layer can also be a layer of so-called cable fibers bonded with a certain bonding pattern or a perforated plastic film.

The liquid-impermeable backsheet 3 can also be of any suitable material, such as plastic film, coated nonwoven fabric.

A liquid-impermeable material, a hydrophobic non-woven material that is resistant to liquid penetration, and / or a laminate of a plastic film with a non-woven material. Breathable materials which are permeable to air and water vapor but which are resistant to liquid ingress, at least up to a certain pressure, can also be used for the backsheet materials.

The topsheet 2 and the backsheet 3 have a slightly larger extension in plane than the absorbent body 4 and extend beyond its edges. The layers 2 and 3 are connected to each other in their protruding parts, for example by means of glue or by heat or ultrasonic welding.

The absorbent body 4 may be of any type used for this purpose. Examples of commonly used absorbent materials are cellulose fluff pulp, tissue layers, highly absorbent polymers (so-called superabsorbents), absorbent foam materials, absorbent non-woven materials or the like. It is common to combine cellulose fluff pulp with superabsorbents in an absorbent body. It is also common to use absorbent bodies comprising layers of different materials with different properties in terms of liquid receiving capacity, liquid distribution capacity and absorption capacity. This is well known to those skilled in the art and therefore need not be described in detail. Thin absorbent bodies that are commonly used in, for example, children's and adult diapers, often contain a compressed blended or layered structure of cellulose fluff pulp and a superabsorbent.

The diaper is intended to embrace the lower torso of the wearer in a manner similar to a pair of absorbent pants. It comprises a front portion 5 intended to be on the front of the user's body in use, a rear portion 6 intended to be on the back of the user's body in use, and a narrower crotch portion 7 between the front and rear portions, and designed to be worn in the crotch of the user, between the legs. On the front part 5 there is a pair of tabs 8 with fastening elements, such as a hook material 9 of a so-called hook-and-loop fastener or other type of fastening elements, such as adhesive tape.

The term "hook material is used to designate parts of mechanical fastening elements having" hook coupling element. However, this is not intended to limit the shape of the coupling members to only containing "hooks", but any shape of coupling members, unidirectional or bidirectional, known in the art as mechanical coupling members with a complementary loop fastening material may be used.

A pair of belt elements 10a and 10b are attached at one end, for example by glue or ultrasonically welded, to the back portion 6 of the diaper. The strap elements 10a, b are intended to be fastened together at their opposite ends, e.g. by a tab 11 on one of the strap elements 10a, said tab may have a hook material 12 thereon forming part of a so-called hook and loop fastener. The purpose of the hook material 12 on the tab 11 is to attach to the outer side of the opposing strap element 10b. Any other type of optional fastening means such as adhesive tape may be used in place of the hook and loop fastener 12.

The tabs 8 with the hook material or the corresponding fastening elements of the front part 5 are to be attached to the outside of the belt elements 10a, 10b in order to connect the diaper to each other so as to assume the desired panty-like shape.

In an alternative embodiment, the belt members 10a, b are attached to the front portion 5 of the diaper and are then attached to each other at the back of the user. In this case, tabs 8 with fastening elements, for example hook material or adhesive tape, are provided on the back part 6 of the diaper.

The outside of the belt portions 10a, 10b should act as a seating surface cooperating with the fasteners on the tabs 8 and 11. In the case of hook and loop fasteners, the material for the outside of the belt portions should serve as the loop material. In this context, the "loop material is not limited solely to materials in which discrete, separately formed loops of material are adapted to receive and engage with the hook members of a complementary hook material, but the loop material also includes a non-woven fibrous material in which the individual fibers function. by engaging the hook members without being formed as discrete loops.

In the case of tape fasteners, the material on the outside of the belt elements 10a, 10b should serve as an attachment surface for the adhesive tapes. Certain non-woven materials will

These acted as both a loop material for the hook and loop fasteners and a reusable attachment surface for the adhesive tape. This is disclosed in WO 01/00129.

The width of the belt elements should be 5 to 10 cm, preferably 7 to 15 cm.

The belt elements according to the invention comprise a flexible laminate of at least three fibrous layers 14, 15 and 16, a first and second outer layer 14, 15 and a middle layer 16 of fibrous material, bonded together in a bonding pattern 13, made by ultrasonic technique. laser and / or thermal. Therefore, at least some of the fibers in the fibrous material layers should be fusible when using such bonding techniques. The bonding pattern 13 should have a bonding area of not more than 10%. Preferably, the fibrous materials are non-woven materials such as spunbond, meltblown, bonded carded webs, thermally bonded webs, etc.

The first outer layer 14 and the middle layer 16 of the laminate have a crinkle structure composed of a plurality of raised areas 14a, 16a separated by a plurality of non-raised areas 14b, 16b formed by the bonding points of said bonding pattern 13. The crinkle structure of the first outer layer 14 is more pronounced due to the greater heights h said raised areas 14a compared to the middle layer 16.

The second outer layer 15 of said laminate is substantially flat and non-wrinkled and is preferably used as the inside of the belt elements to face the user and should therefore be smooth and skin-friendly. The first outer layer 14 of the laminate is used as the outer side of the belt elements to act as a landing surface for said fastening elements, and is especially used as a loop material for the complementary hook material of the hook and loop type fasteners 8 and 9. The crinkle structure of layer 14 will provide increased bulk and a three-dimensional structure suitable for engaging the hook material. Thus, the loop function of the gathered material is improved compared to the substantially flat and smooth nonwoven material. Examples of non-woven materials suitable for the first outer layer 14 are spunbonds, meltblowns, bonded carded materials, etc. The second outer layer 15, intended to form an inner belt layer facing the wearer, should be of a soft and skin-friendly fibrous material. Examples of suitable materials are spunbond and meltblown materials, carded bonding materials, etc. Examples of polymeric materials used in the various fibrous materials can be any suitable materials, for example polypropylene, polyethylene, polyester and / or so-called bicomponent fibers. The middle layer 16 is used as the support layer to provide the laminate with mechanical strength and stability. The middle layer 16 should be of a relatively tear-resistant fibrous material, such as a spunbond or meltblown material containing filaments.

The laminate should have a tear strength of at least 22N. Consequently, the belt members will resist tearing when securing the belt around the user's waist. Tests have shown that the tear frequency in normal use for belts having a tear strength of 21 N and less was unacceptably high. Preferably, the tear strength should be at least 24 N, more preferably at least 25 N, and most preferably at least 27N. For belts having a tear strength of 29 N or higher, no tearing has occurred at all.

The tear strength is measured by EDANA method, TEAR 70.3-96 method modified to use a conditioning time of 4 hours, a temperature of 23 ° C, and a relative humidity of 50%.

A bond area of no more than 10% increases the number of tear points or notches and an increased risk of tearing the belt elements.

Preferably, the bonding area should not be greater than 8%, and more preferably not greater than 5%.

The bonding pattern includes a plurality of bonding sites in the form of dots, lines, specks or the like, arranged in a pattern. The bonding area of the bonding pattern is defined as the size of the pattern composed of the bonding sites.

Another important factor for ensuring high tear strength is the bonding density, which is the number of bonding sites per unit area. The bond pattern 13 preferably has a bond density of between 1 and 15 bond sites per cm ² . Preferably, the density of the bonds

The ratio is 1 to 10 per cm ² . The higher the density of the seams, more tears or notches are created, which reduces the tear strength.

Relatively large bonding sites, e.g. in the form of a line, provide a relatively large bonding area with fewer bonding sites, compared to a bonding pattern composed of small bonding sites, e.g. in the form of dots, arranged at a higher bond density. Thus, both the bond area and the bond density are important.

One non-limiting embodiment of a laminate according to the invention is a three-layer laminate:

thermally bonded carded material with a weight of 30 g / m ² , made of polypropylene fibers with a thickness of 2.2 dtex;

40 g / m ² spunbond layer made of 2.2 dtex polypropylene fibers; 22 g / m ^2, thermally bonded carded material made of polypropylene fibers with a thickness of 2.2 dtex.

The spunbond layer is used as the middle layer, the heaviest carded material is crimped and intended to be used as the outside of the belt and is adapted to act as a loop material for a hook-and-loop fastener, and the lightest carded material is used as the inner, facing side of the waist towards the wearer. The middle spunbond ply is also crinkled, but with a less pronounced crinkle structure compared to the carded material to be used on the outside of the belt.

The laminate is ultrasonically bonded so that the bonding area is approximately 3% and the bond density is approximately 7 bond points per cm ² . The tear strength is 55 N.

The method of producing a laminate material according to the invention comprises bonding together at least three layers 14, 15 and 16 of a fibrous material in accordance with the bonding pattern 13 by ultrasonic, laser and / or thermal techniques in a bonding station 17 schematically shown in Fig. 3. Bonding station 17 in one embodiment of the invention it comprises an ultrasonic arm 18 placed opposite the embossing roller 19. In order to obtain a crinkle structure, the layers are brought to the bonding station 17 so that the webs have different stresses and / or speeds of movement, the layer 14 having the smallest the tension of the web and / or the speed of movement is slowed down and is folded or crinkled at the upstream end of the bonding station. The layer 15 with the greatest web tension and / or web speed remains substantially smooth, while the middle layer 16 with web tension and / or web speeds that are higher than layer 14 but lower than layer 16 is also crimped or crinkled. but less than layer 14. After bonding, the laminate is fed from the bonding station at a web tension / web speed substantially equal to that of the web with the lowest tension / speed, namely layer 14.

According to one embodiment, the second outer layer 15 has the web tension and / or the web speed entering the bonding station by 15 to 50%, and preferably 18 to 33% higher than for the first outer layer 14. According to a further embodiment, the middle layer is 16 has the web tension and / or speed of the web entering the bonding station 5 to 40%, preferably 9 to 18% higher than for the first outer layer.

Claims (13)

An absorbent article, such as a baby diaper and an adult diaper, comprising a liquid-permeable topsheet (2), a liquid-impermeable backsheet (3) and an absorbent body (4) disposed therebetween, the article having a front portion. (5), a rear portion (6) and a crotch portion (7) interposed therebetween, and is further provided with a pair of strap elements (10a, 10b) attached to the rear portion (6), alternatively to the front portion of the article, to be secured with each other around the waist of the wearer by means of fastening elements (11, 12) and where on the front part (5), alternatively the rear part, there are fastening elements (8, 9) intended to be attached to the belt elements (10a, 10b) in such a way. a method for the article to take a pant-like shape, wherein the belt elements (10a, 10b) form part of the waist portions of the panties, characterized in that the belt elements (10a, 10b) comprise a flexible laminate of at least three first layer layers. the outer seam (14), the middle layer (16) and the second layer The external (15) fibrous material bonded together according to the bonding pattern (13) made by ultrasonic, laser and / or thermal techniques, the bonding pattern (13) having a bonding area not greater than 10%, and the first the outer layer (14) and the middle layer (16) of the laminate have a crinkle structure composed of a plurality of raised areas (14a, 16a) separated by a plurality of non-raised areas (14b, 16b) formed by the seams of the bond pattern (13), where the crinkle structure of the first outer layer (14) is, compared to the middle layer (16), clearer with the greater heights (h) of the raised areas (14a). 2. The product according to claim The method of claim 1, wherein the second outer layer (15) of the laminate is substantially smooth and non-wrinkled. 3. The product according to claim The laminate as claimed in claim 1 or 2, characterized in that the second outer layer (15) of the laminate is used as the inner side of the belt elements (10a, 10b) to face the user, and the first outer layer (14) of the laminate is used as the outer side of the belt elements. intended to act as a seating surface for fastening elements (8, 9). 4. The product according to p. The method of claim 3, characterized in that the first outer layer (14) is used as a loop material for the complementary hook material of the hook and loop type fasteners (8, 9). 5. The product according to claim The method of claim 1, characterized in that the bonding pattern (13) has a bonding area of not more than 8%, preferably not more than 5%. 6. The product according to p. The method of claim 1 or 5, characterized in that the bonding pattern (13) has a bonding site density of 1 to 15 bonding sites per cm ² . 7. The product according to p. The method of claim 6, characterized in that the bonding pattern (13) has a bonding site density of 1 to 10 bonding sites per cm ² . 8. The product according to claim 1 The process of claim 7, characterized in that the middle layer (16) is made of a relatively high tear strength fibrous material containing continuous fibers, such as spunbond and / or meltblown material. A method of manufacturing a flexible laminate for use as belt elements (10a, 10b) on an absorbent article, such as a baby diaper and an adult diaper of the type as set out in claim 1, characterized in that it is bonded together in a bonding station. (17) at least three layers, a first outer layer (14), a middle layer (16) and a second outer layer (15) made of fibrous material according to a bonding pattern (13) made by ultrasound, laser and / or heat, the pattern being the bond (13) has a bond area of not more than 10%, and the laminate layers (14, 15, 16) have different web tensions and / or web speeds at the entrance to the bonding station (17) such that the first outer layer (14) ) has the lowest web tension and / or the lowest web speed, the second outer layer (15) has the highest web tension and / or the highest web speed, and the middle layer (16) has web tension and / or web speed that are greater than n that for the first outer layer] (14) and smaller than for the second outer layer (15). 10. The method according to p. The method of claim 9, characterized in that the second outer layer (15) has a web tension and / or web speed during bonding 15 to 50% higher than for the first outer layer (14). 11. The method according to p. The method of claim 10, characterized in that the second outer layer (15) has a web tension and / or web speed during bonding 18 to 33% greater than that of the first outer layer (14). 12. The method according to p. A method according to claim 9 or 10 or 11, characterized in that the middle layer (16) has a web tension and / or a web speed during bonding 5 to 40% higher than for the first outer layer (14). 13. The method according to p. 12. The process of claim 12, characterized in that the middle layer (16) has a web tension and / or web speed during bonding 9 to 18% greater than for the first outer layer (14).